/* BARE_OS_BIN_API 1.0.0 — bump when staged /bin script semantics change (see developer guide). */
/** Shared helpers for drive-resident /bin scripts (prepended before each command). */
function bareStdin(ctx) {
  return typeof ctx.shellStdin === 'string' ? ctx.shellStdin : ''
}

/** @param {number} mode @param {'file' | 'directory' | 'symlink'} type */
function bareFormatModeString(mode, type) {
  const typeChar = type === 'directory' ? 'd' : type === 'symlink' ? 'l' : '-'
  const perm = mode & 0o777
  const r = (bit) => (perm & bit ? 'r' : '-')
  const w = (bit) => (perm & bit ? 'w' : '-')
  const x = (bit) => (perm & bit ? 'x' : '-')
  return (
    typeChar +
    r(0o400) +
    w(0o200) +
    x(0o100) +
    r(0o040) +
    w(0o020) +
    x(0o010) +
    r(0o004) +
    w(0o002) +
    x(0o001)
  )
}

/** @param {number} mtimeMs @param {number} [nowMs] */
function bareFormatLsMtime(mtimeMs, nowMs) {
  const now = nowMs != null ? nowMs : Date.now()
  const d = new Date(mtimeMs)
  const months = [
    'Jan',
    'Feb',
    'Mar',
    'Apr',
    'May',
    'Jun',
    'Jul',
    'Aug',
    'Sep',
    'Oct',
    'Nov',
    'Dec'
  ]
  const mon = months[d.getMonth()]
  const day = String(d.getDate()).padStart(2, ' ')
  const sixMo = 180 * 24 * 3600 * 1000
  if (Math.abs(now - mtimeMs) > sixMo) {
    const yr = String(d.getFullYear()).padStart(4, ' ')
    return mon + ' ' + day + '  ' + yr
  }
  const hh = String(d.getHours()).padStart(2, '0')
  const mm = String(d.getMinutes()).padStart(2, '0')
  return mon + ' ' + day + ' ' + hh + ':' + mm
}

/** @param {number} size */
function barePosixBlocks(size) {
  return Math.ceil(Number(size) / 512) || 0
}

/**
 * Raw stdout for NUL/binary when **`process.stdout.write`** is missing.
 * If **`ctx.bareOsBinWrite(Uint8Array|string)`** is set (tests / host), use it.
 * @param {Record<string, unknown>} ctx
 * @param {string | Uint8Array} chunk
 * @returns {boolean}
 */
function bareOsEmitRaw(ctx, chunk) {
  if (typeof ctx.bareOsBinWrite === 'function') {
    const b4 = ctx.b4a
    const u8 =
      typeof chunk === 'string'
        ? b4 && typeof b4.from === 'function'
          ? b4.from(chunk)
          : new TextEncoder().encode(chunk)
        : chunk
    ctx.bareOsBinWrite(u8 instanceof Uint8Array ? u8 : new Uint8Array(u8))
    return true
  }
  const w = globalThis.process?.stdout?.write
  if (typeof w === 'function') {
    w.call(globalThis.process.stdout, chunk)
    return true
  }
  return false
}

/**
 * Subset of ulimit(1): reports soft limits aligned with getconf(1) caps (no host rlimit).
 */

const LIMITS = [
  ['open files', '-n', '256'],
  ['max user processes', '-u', '32'],
  ['pipe size', '-p', '512'],
  ['file size', '-f', 'unlimited'],
  ['cpu time', '-t', 'unlimited'],
  ['virtual memory', '-v', 'unlimited']
]

/**
 * @param {Record<string, unknown>} ctx
 */
async function readRuntimeLimits(ctx) {
  try {
    const b = await ctx.vfs.readFile('/proc/bare_os/rlimits.json')
    if (!b) return null
    const j = JSON.parse(ctx.b4a.toString(b))
    return j && typeof j === 'object' ? j : null
  } catch {
    return null
  }
}

async function run(ctx, argv) {
  const args = argv.slice(1).filter((a) => a !== '--')
  const rt = await readRuntimeLimits(ctx)
  const nofileSoft =
    String(
      rt?.softNoFile ??
        rt?.soft_nofile ??
        rt?.nofileSoft ??
        rt?.nofile_soft ??
        256
    ) || '256'
  const nofileHard =
    String(
      rt?.hardNoFile ??
        rt?.hard_nofile ??
        rt?.nofileHard ??
        rt?.nofile_hard ??
        nofileSoft
    ) || nofileSoft
  if (args.length === 0 || (args.length === 1 && args[0] === '-a')) {
    for (const [label, flag, val] of LIMITS) {
      const outVal = flag === '-n' ? nofileSoft : val
      ctx.console.log(`${label} (${flag}) ${outVal}`)
    }
    return
  }
  if (args.length === 1 && (args[0] === '-n' || args[0] === '-Sn')) {
    ctx.console.log(nofileSoft)
    return
  }
  if (args.length === 1 && args[0] === '-Hn') {
    ctx.console.log(nofileHard)
    return
  }
  ctx.console.error('ulimit: only -a, -n, -Sn, and -Hn are supported in Bare OS')
  ctx.exitCode = 1
}